Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
  • D21H21/14—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by function or properties in or on the paper
  • D21H21/30—Luminescent or fluorescent substances, e.g. for optical bleaching
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L89/00—Compositions of proteins; Compositions of derivatives thereof
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L89/00—Compositions of proteins; Compositions of derivatives thereof
  • C08L89/005—Casein
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
  • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
  • D21C9/10—Bleaching ; Apparatus therefor
  • D21C9/1063—Bleaching ; Apparatus therefor with compounds not otherwise provided for, e.g. activated gases
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
  • D21H17/20—Macromolecular organic compounds
  • D21H17/21—Macromolecular organic compounds of natural origin; Derivatives thereof
  • D21H17/22—Proteins

Definitions

• white celluloses and/or extra-white celluloses and pure white mineral fillers such as caolin, calcium carbonate and so forth are used by paper industry.
• the white degree so obtained by the use of these selected raw materials can be further increased by using said optical bleaching agents.
• Optical bleaching agents are fluorescent substances able to absorb UV radiation and to emit light with lower energy and, thereafter, with higher wavelength in the visible range of the solar spectrum corresponding to the blue- violet wavelength. In this way, when the same amount of incident light is absorbed, the reflected visible light increases, thereby the sheet looks whiter to the naked eye than what it actually is. This is allowed by the compensation of the blue-violet emission of the optical bleaching agent towards the yellowish component of paper, thereby the whole effect is due to the mixing of substrate colour with the fluorescent light. It is therefore obvious that the characteristic colour of the substrate strongly affects the final bleaching result.
• the optical bleaching agent efficiency is, as a consequence, always related to the material to be bleached.
• the two basic components used in paper industry are several kinds of celluloses and woodpulps, the quantitative ratios of which determine the preparation of different kinds of paper products, which are available on the market.
• TGW ThermoGrinding Wood
• CTMP Cosmetic Pulp
• woodpulps so bleached cannot be further bleached to a higher white degree, even by using a high concentration of optical bleaching agent and, besides, their yellowing tendency cannot be changed ("ULMANN'S ENCYCLOPEDIA OF INDUSTRIAL CHEMISTRY", 1991, vol. A18, pg. 601-602).
• woodpulps have also scarce touch features, i.e. the surface of the sheets obtained with high amounts of woodpulp is rough, thereby, it is not very satisfactory to touch, contrary to sheets obtained with high amounts of cellulose, which have smooth surfaces.
• woodpulp is a fibrous product which is combined with the cellulose in order to give a stiffness degree to the final paper product.
• Such feature is a cubic function of the material thickness, and as woodpulp density is lower than that of cellulose, being the weight equal, the woodpulp is thicker and stiffer than the cellulose.
• the woodpulp also has a higher opacity degree and remarkably lower costs up to 25-30% less than the costs of cellulose.
• the additive ingredient which is added to the optical bleaching agents in order to obtain the bleaching composition according to the present invention can be caseine, caseine derivatives, soya proteins or their mixtures.
• the composition according to the invention will be better understood from the following detailed description followed by two illustrative and not limitative preferred embodiments of the invention. Wherever the term “parts” is used, it means “parts by weight”, unless otherwise specified.
• the woodpulp can be any woodpulp however obtained, especially selected from the group consisting of SGW (Stone GroundWood), RMP (Refined Mechanical Pulp), TMP
• the woodpulp to be treated with the composition of the invention is preferably either CTMP, which is obtained by a mechanical process along with chemothermal treatment, or CMP, which is obtained by mechanical process together with treatments with alkali compounds or acids.
• CTMP which is obtained by a mechanical process along with chemothermal treatment
• CMP which is obtained by mechanical process together with treatments with alkali compounds or acids.
• the composition according to the invention can be directly applied on the obtained woodpulp or preferably on the woodpulp pretreated with bleaching cycles, which are of generally known industrial kind and preferably cycles of peroxide/sodium dithionite.
• the additive ingredient is dissolved in an alkaline solution at a concentration between 1%) and 30%> based on weight solution, and preferably 13% of caseine or derivative thereof or 16% of soya proteins.
• Said alkaline solution of the additive ingredient is added to the optical bleaching agent solution at ratios of additive ingredient solution to optical bleaching agent solution between 0.1 and 10, preferably 0.5-5 and more preferably equal to 1.
• the optical bleaching agent can be added as a powder or more preferably it can be dissolved in water.
• Said optical bleaching agent is a derivative of compounds selected from the group consisting of carbocycles, distyrilbenzenes, distyrilbiphenyls, divinylstilbenes, bistriazinylaminostilbenes, stilbenyl-2H-triazoles, stilbenyl-2H-naphtho[ 1 ,2-d]triazoles, bis(l,2,3-triazol-3-yl)stilbenes, benzoxazoles, stilbenylbenzoxazoles, bis(benzoxazoles), furans, benzo[b]furans, benzimidazoles, bis(benzo[b]furan-2-yl)biphenyls,cationic benzimidazoles, l,3-diphenyl-2-pyrazolines, coumarins, naphthalimides, l,3,5-triazin-2-yl derivatives and mixtures thereof.
• Said optical bleaching agent is preferably a compound derived from the family of stilbenes and more preferably is a derivative of bistriazinylaminostilbene. Therefore the optical bleaching agent can be directly added to the caseine or a derivative thereof solution without any pre-treatment.
• the caseine derivatives are preferably caseinates of different alkaline or earth alkaline metals, such as e.g. sodium caseinate, and these are dissolved before adding the optical bleaching agent.
• a mixture of caseine and a derivative thereof is used under the same conditions stated for the single components.
• the solution of additive ingrendient and optical bleaching agent is mixed at a temperature between 15 °C and 80 °C, preferably 30-50 °C and more preferably 40 °C for about 10-30 minutes.
• excipients such as preservatives, pH stabilizers are added in order to have a formulation to be placed on the market as a ready for use product.
• the composition can be prepared when being used.
• the composition according to the invention is metered on the base of the amount of dry fiber to be bleached and on the base of the desired white degree. It is preferably added in amounts between 0.1 and 10%> based on the fiber dry weight to be bleached.
• the maximum white degree achievable by applying the composition of the invention is obtained by treating the material to be bleached at pH ⁇ 7 after it has already been treated with the composition of the invention, preferably at pH 5.5, with a compound selected from the group consisting of aluminum salts, mineral acids, organic acids, preferably aluminum sulfate.
• composition according to the invention can, of course, be used on any material having a scarce "basic white”, therefore on non bleached, semibleached celluloses, semicelluloses or can be also used in any bleaching treatment on paper substrates, producing the same effects of the application on woodpulp.
• Example 1
• caseine 100 parts are dispersed in 400 parts of water by stirring for ten minutes.
• Example 2 50 parts of the solution so obtained are then mixed with 50 parts of a liquid optical bleaching agent or a powder optical bleaching agent dissolved in water so as to have a solution with a maximal possible concentration.
• the product so obtained can be used directly or be added with optional additives for the preparation of a ready-to-sell product.
• Example 2
• soya proteins are dispersed in 500 parts of water by stirring for ten minutes. Thereafter 10 parts of sodium tetraborate and 100 parts of water are added and the solution is heated at a temperature of 40 °C for 10 minutes. 10 parts of an alkali, preferably ammonia, are then added, heating at 60 °C and stirring for further 20 minutes. Finally, 200 parts of water are added and the solution is stirred for 20 minutes at 60 °C.
• Sample 1 woodpulp sheet, pretreated with bleaching cycles, manufactured with a static sheetmaker (FS) with grammage of about 120 g/m 2
• Sample 2 woodpulp sheet as sample 1 treated with 2%> of optical bleaching agent and caseine solution at 1 : 1 ratio based on woodpulp dry weight.
• Sample 3 sheet of bleached cellulose having short fibers.
• Sample 4 woodpulp sheet, pretreated with bleaching cycles, manufactured by dynamic sheetmaker (Fd) of TechPap with a grammage of 120g/m 2 treated with 2% of optical bleaching agent and caseine solution at 1 : 1 ratio based on woodpulp dry weight. These four samples were tested for the white degree through reflection according to the UNI 7623-86 method. Data which is set forth in Table 1 were obtained.
• Sample 2 treated with the composition according to the invention shows a higher reflection percentage than sample 3, made of bleached cellulose having short fibers.
• Sample 4 shows results almost equal to sample 2, underlining that the surprising white effect is feasible on industrial scale, being sample 4 obtained through a dynamic system, which simulates the industrial conditions of making the sheet. Reflection test 2
• Sample 2A woodpulp A treated with 1% of a optical bleaching agent available on the market
• Sample 3 A woodpulp A treated with 2% of the solution of the invention at optical bleaching agent/caseine ratio equal to 1.
• Sample 4 A woodpulp A treated with 4%> of the solution of the invention at optical bleaching agent/caseine ratio equal to 1.
• Sample IB woodpulp B
• Sample 2B woodpulp B treated with 1% of a optical bleaching agent available on the market.
• Sample 3B woodpulp B treated with 2%> of the solution of the invention at optical bleaching agent/caseine ratio equal to 1. The reflection was tested in order to establish the white degree according to the UNI 7623- 86 method, and the data thereof are set forth in Table 2.
• Reflection test 1 was repeated using the same woodpulp bleached under the same conditions and amounts, except for caseine which was replaced by soya proteins.
• Reflection data (%ISO) are set forth in the following Table 3.

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Wood Science & Technology (AREA)
• Paper (AREA)
• Chemical And Physical Treatments For Wood And The Like (AREA)
• Detergent Compositions (AREA)

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• 1997
  • 1997-12-10 IT IT97MI002729A patent/IT1296947B1/it active IP Right Grant
• 1998
  • 1998-06-10 WO PCT/EP1998/003665 patent/WO1999029779A1/fr active IP Right Grant
  • 1998-06-10 AT AT98932163T patent/ATE230777T1/de active
  • 1998-06-10 DK DK98932163T patent/DK1047729T3/da active
  • 1998-06-10 DE DE69810663T patent/DE69810663T2/de not_active Expired - Lifetime
  • 1998-06-10 EP EP98932163A patent/EP1047729B1/fr not_active Expired - Lifetime
  • 1998-06-10 AU AU82161/98A patent/AU8216198A/en not_active Abandoned
  • 1998-06-10 ES ES98932163T patent/ES2190594T3/es not_active Expired - Lifetime

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